1. Technical Field
The present invention relates to a method for forming a wiring pattern, a wiring pattern, and an electronic apparatus.
2. Related Art
A wiring pattern composing an electronic apparatus is formed by using, for example, lithography. However, lithography requires huge facilities, such as a vacuum system, and complicated processes. Besides, the manufacturing cost is high because the yield rate is only a few percent and the bulk of material must be thrown out. Further, there is a limit to the refining of a wiring pattern.
Therefore, as an alternative process to lithography, a method for discharging a droplet containing a functional material onto a substrate to draw and form a wiring pattern directly onto the substrate (a droplet discharge system) is considered. In the method, first, a droplet in which conductive microparticles are dispersed is discharged onto a substrate from a droplet discharge head to form a liquid line. Then, the liquid line is baked with heat treatment or laser irradiation or the like to form a wiring pattern (refer, for example, to the specification of the U.S. Pat. No. 5,132,248). According to the droplet discharge system, the manufacturing process is simplified, and the manufacturing cost can be lowered due to a high yield rate. Further, the refining of a wiring pattern is easily realized.
Multilayering as well as refining of wiring patterns is important to downsize electronic apparatuses. To multilayer wiring patterns, electrical wirings are deposited via interlayer insulator films, the electrical wirings on the plural layers being conductively connected to each other through conductive posts.
The above-referenced conductive posts need to be formed with an appropriate height to pierce the interlayer insulator films. Therefore, plenty of droplets need to be discharged by a droplet discharge system to form a post with an appropriate height. However, discharging plenty of droplets at a time is not sufficient to achieve a needed height for a post. Rather, there is a possibility that it generates a post that is too large in diameter, causing a short circuit between adjacent electrical wirings or between adjacent conductive posts. Therefore, the establishment of a method for forming a conductive post with an appropriate height by a droplet discharge system is desired.